Switch structure



to the electric drill.

Patented Aug. 22, 1944 UNITED swlrc'ir STRUCTURE William B.'-Kochner,St. Louis, Mo., assignor to 'l Knapp-Monarch=`Company, St. Louis, Mo., a

corporation or'v Missouri l v Application June 1, 1942, VSerial No.445,340

s claims. (C1. 20c- 157) My present invention relates to a switchstruc-A ture particularly adaptable for electric drills and thelike anddesigned for being built into the handle thereof.

One object of the invention is to provide a switch structure whichminimizes the use of metal by its design, being almost entirely ofBakelite or any suitable insulating material or plastic, with only the`current-carrying parts being formed of metal. Y

A further objectis to provide a switch structure which is simple fromthe standpoint of the number of parts involved in its construction andeasy to assemble and wire into the circuit of the device to becontrolled thereby.

Another object is to provide an inexpensive switch structure which hassnap action to minimize arcing at the contacts, and which has a numberof design features so related as to .accomplish all the necessaryresults involved, with a minimum of parts.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice whereby the objects contemplated are at, tained, as hereinaftermore fully set forth, Vpointed out in my claims and illustrated in thevaccom-` panying drawing, in which:

Figure l is a side elevation of my switch struc-V ture as applied to ahandle of an electric drill or the like, parts of the handle beingbroken away i and other parts being shown in section to .show

Where the wires may enter and leave the handle; Figure 2 is an enlargedvertical view through a portion of the handle and through my switch.

structure;

Figure 3 is an enlarged sectional View on the line 3-3 of Figure 1;Figure 4 is a sectional view on the line` 4-4 of Figure 2;

lFigure 5 is a bottom perspective view of a switch actuator of my switchstructure; and

Figure 6 is a sectional view similar to Figure 2,

showing the parts in a different position.U

On the accompanying drawing I have used the reference character H toindicate generally a housing in the form of a handle for an electricdrill or the like. The handle H has a, iiange I0 for attachment to themotor of the drill and -is provided. with openings I2 and III forcurrent wires to extend respectively into the handle from arsource oflcurrent supply and from the handle The handle H is hollow, being formedof Bakelite or other plastic material in two halves, parted verticallyat thecenter,

and the two halves, after Abeingforme'd,` are retained in assembledrelati n to each other by rivets or bolts l5. f

Each half of the handle H includes a side Wall IB'and a top iiangeA Il.The flangesV Il extend toward and contact with each other at the centerof the handle and are retainedv in contact by the Yrivets or bolts '|5.The' parting line is shown at I8 in Figure 3, and the flanges I'I arenot sectioned in Figures 2 and 6 to thereby indicate that the section inthese gures is taken at the parting line'.

A shelf velementlS extends inwardly from each side Wall I6, and'theseshelf elements terminate spaced from eachother, as shown in Figures 3and 5, the space being indicated at 2 [Lf "A pair of notches 2| isprovided in each shelf element I9 to receive downwardly extendingterminal ends 22 of stationary contact strips 23. The contact stripshave down-turned terminal ends 2li notchedv as at 25 to receive circuitwires that are to be soldered thereto. The terminal ends 24, it will benoted, contact the ends of the shelf elements I9 whereby, in conjunctionwith the" terminal ends 22 being con'iined inthe notches 2|, thecontact' stripsA 23 are confined against longitudinal movement relativeto the shelf elements. y

The side walls I6 are thickened as shown at 26 in Figure 4, and betweenthe thickened portions 25 a switch actuator A is mounted for slidingmovement. The sides of the actuator Aare confined by the thickenedportions 26', whereas the bottom of the actuatorv A slides on the shelfelementull Vand the top thereof slides beneath the surfaces 2 ofthegflanges Il, `which surfaces are Aparallel to the shelf elements I9.The switch actuator'A has a thumb engageable portion 28 extendingthrough a/slot 292'in`the handle H, such slot being formed byregistering notches in the flanges Il. From -the construction ofY theparts just described it lwill beI obvious that .the actuator A isconfined-to `Sliding movement along a predetermined axis, and is limitedin such sliding movement by thevends' of the notches 2,9.

The switch actuator Av has a recess 30 in its bottom surface,therebyleaving end walls 3|. The end walls 3| arenoizchei as'atv32,l thenotches 32 ,being narrowerA than the recess 33. The notches 32 areslightly` wider'than ther stationary contact strips 23 andI straddle-them to l:coniine them against lateral movement onjthe shelfelementsl9.. y M

In the'recess 3451A mount.'a/movablejcontact strip `V33 which isslightly less `infwidth than the width of the recess, slightly less inlength than the length of the recess, and wider than the notches 32. Thecontact strip 33 has a pair of humps 34 to coact at times with humps 35formed on the stationary contact strips 23. A spring 36 is positionedbehind the movable contact 33 and is positioned in a socket 31 extendingup into the thumb engageable portion 28 of the switch actuator. Themovable contact 33 is thereby floatingly mounted in the recess 30 andbiased to engage the contact strips 23.

Practical operation In the operation of my switch structure, beginningwith the closed circuit position of Figure 2, it will be noted that thehumps 34 of the movable contact 33 are completely seated on the humps 35of the stationary contacts 23. Accordingly, a circuit is establishedacross the contacts 23 by the bridging contact 33. j

When it is desirable to move the switch to off position the thumbengageable portion 28 is engaged and the switch actuator A thereby slidrearwardly. As illustrated in `Figure 6, this causes the movable contact33 to ride up on the humps 35 of the stationary contacts23 until,finally, the right-hand end of the contact 33 leaves the hump 35 of theright-hand contact 23, thereby breaking the circuit. 'Ihe break willy bewith snap -action, because of the resistance to movement beingencountered by the compression of the spring in Figure 6 until themovable contact is on the tops of the humps k35, whereupon there is nofurther tendency to raise the movable contact against the tension of thespring. The operators thumb will accordingly move the actuator A quicklyto the open circuit position because of this reduction in resistance toits movement. The open position of the switch is shownby dotted lines inFigure 2, wherein it will be noted that the central portion of themovable contact 33 is riding on top of the hump 35 of the left-handstationary contact 23.

In closing the switch, the actuator A is moved forwardly of the handleH, causing contact to first be made between the right-hand end ofcontact 33 and the hump 35 of the right-hand contact 23 with a snappingof the switch to closed position after the position of Figure 6 isreached, and the spring 36 thereupon forces the humps 34 down over thehumps 35.

Some changes maybe made in the construction and arrangement of theparts: of my device without departing from Ythe real spirit and purposeof my invention, and it is my intention to coverby my claims anymodified forms of structure, or use of mechanical equivalents, which maybe reasonably included within their scope.

I claim as my invention:

1. In a switch structure for handles and the like, said handleconstituting a housing vfor the switch structure. and being for-med intwo parts with a cavity between said parts, said handle parts havingshelf elements projecting toward each other, a pair of stationarycontacts on said shelf elements, a switch actuator slidable on saidshelfv elements and confined between the shelf elements and the handlewhen the two parts of the handle are held assembled together, f saidswitch actuator having a recess, and a movable contact mounted thereinand adapted in one position of the switch actuator to bridge both ofsaid stationary contacts 2. In a switch structure for electric drillsand the like, a handle for the drill formed in two parts with a cavitybetween said parts constituting a housing for the switch mechanism, saidhandle parts having shelf elements projecting toward each other, a pairof elongated stationary contacts on said shelf elements and having partscoacting therewith to prevent movement of said stationary contacts onsaid shelf elements, a switch actuator slidable on said shelf elementsand being confined between the shelf elements and the handle, saidswitch actuator having guide notches straddling said stationary contactsto be guided thereby and having a recess, and a movable contactfloatingly mounted therein and adapted in one position of the switchactuator to bridge said stationary contacts.

3. In a switch structure, a hollow handle formed in two parts andconstituting a, housing for the switch mechanism, said handle partshaving shelf elements projecting toward each other, each of said shelfelements having a pair of notches, a pair of stationary contacts on saidshelf elements having portions received in said notches when said twohandle parts are assembled together, a switch actuator slidable betweensaid shelf elements and a wall of the handle, said switch actuatorhaving a, recess, a oating contact mounted therein and adapted in oneposition of the switch actuator to bridge both of said stationarycontacts and in the opposite position of the switch actuator to breakcontact between them, and a, spring biasing said oating contact towardsaid shelf elements and said switch actuator toward said wall of thehandle.

4. A switch structure for electric drill'handles and the like formed intwo parts with a cavity between said parts constituting a housing forthe switch mechanism, said handle parts having shelf elements providedwith registered notches, a pair of elongated stationary contacts on saidshelf elements and each having parts received in said notches of saidshelf elements to preventlateral movement of the stationary contactsthereon, a switch actuator slidable on said shelf elements and confinedbetween the shelf elements and said handle, said switch actuator havinga recess and having guide notches straddling said stationary contactsand thereby guided for slidingmovement, a movable contact in said recessfor bridging coaction with said stationary contacts, said guide notchesbeing narrower than said recess to prevent longitudinal movement of saidmovable contact within said recess relative to said switch actuator withthe ends of said recess oonning the ends of said movablecontact, saidswitch actuator having a thumb engageable portion and said handle havinga slot through which said thumb engageable portion extends totheexterior of the handle.

5. In a switch structure, a housing, said housing being formed in twoparts with a shelf element projecting from each part and havingregistered notches, a pair of stationary contacts on said shelfVelements having terminarendsreceived in said notches, a switch actuatorslidable between said shelf elements and a wallyof said housing, saidswitch actuator having ,arecess therein, a movable contact carriedinsai'd recess for bridging coaction with said stationary con-J` tacts,said switch actuator having arthumb engageable portion and said wall Vofthe" housing having a slot through which said thumb engageable portionextends to theY exterior ofthe hous- 6. A-'switch structurercomprising atwo-part:

housing having shelf elements projecting toward each other and providedwith registering notches, a, pair of stationary contacts each comprisinga longitudinal body portion, a hump adjacent one end thereof andterminal ends bent downwardly therefrom, some of said terminal endsbeing received in said notches and others engaging the ends of saidshelf elements to coniine said stationary contacts against longitudinalmovement on said shelf elements, a switch actuator slidable between saidshelf elements and a wall of said housing, said switch actuator havingguide notches coacting with said stationary contacts to retain them inproper alignment and having an enlarged recess between said notches, amovable contact in said recess and having a pair of humped portions tocoact with the humped portions of said stationary contacts in the closedposition of the switch, a spring in said recess behind said movablecontact, said movable contact and said recess being wider than saidnotches to confine said movable contact against endwise movementrelative to said switch actuator.

'7. In a switch structure, a support, a pair of stationary contactsthereon, a switch actuator slidable on said support and having a recesstherein adjacent said stationary contacts, a floating movable contactconfined in said recess against lateral movement relative to said switchactuator, said stationary7 contacts and said movable contacts havingcoacting humps and depressions respectively, a spring in said recess andbearing against a portion of said movable contact intermediate saiddepressions and thereby tending to engage said movable contact with saidstationary contacts, and means for confining said switch actuator tomovement through a limited space, one limit of the movement permittingsaid depressions of said movable contact to engage said humps of saidstationary contacts and the other limit of movement permitting saidmovable contact to ride with said portion thereof supported on the humpof only one of said stationary contacts and with the backs of saiddepressions closely adjacent the bottom of said recess to thereby holdsaid movable contact against tilting.

8. A switch structure comprising a hollow handle being formed in twoparts with a cavity between ksaid parts constituting a housing for theswitch mechanism, said handle parts having shelf elements projectingtoward each other, a pair of elongated stationary contacts on said shelfelements and each having a hump and a terminal end substantially normalto the plane of the stationary contacts, said shelf elements havingnotches registering with each other and receiving said terminal endswhen said two handle parts are assembled, a switch actuator slidable onsaid shelf elements and confined between the shelf elements and a wallof said handle, a movable contact carried by said switch actuator andhaving depressions to receive said humps when said movable contactbridges said stationary contacts, said movable contact in off positionof the actuator being supported on only one of said humps, said actuatorhaving a thumb engageable portion and said wall of each part of saidhandle having a second notch, said second notches'registering to form aslot when said two parts are assembled through which said thumbengageable portion slidably extends to the exterior of the handle.

WILLIAM B. KOCHNER.

